package homework;

import org.junit.Test;

public class Callback {
   @Test
    public void test01(){
        System.out.println(f(10));
    }
    long f1=1l;
   long f2=2l;
    public long f(long n){
       for(long j=3l;j<=n;j++){
           f2=j*f2;
           f1=f2/j;
       }
        return f2;
        }

    }

